1. Lecturer, School of Engineering and the Built Environment, Edinburgh Napier University, Merchiston Campus, Edinburgh, EH10 5DT, UK (corresponding author: )
2. Senior Lecturer, School of Science and Engineering, University of Dundee, Fulton Building, Dundee, DD1 4HN, UK
3. Professor, Department of Engineering, Durham University, South Road, Durham DH1 3LE, UK